Explicitly defined, described or recognized as a reference.
Of a religion, church etc.: formally recognized by a state as being official within that area.
Having been in existence for a long time and therefore recognized and generally accepted.
To release (an animal) from a stable.
Readily decomposable.
Not stable.
Radioactive, especially with a short half-life.
Unpredictable.
Fickle.
Having a strong tendency to change.
Fluctuating; not constant.